Which do you prefer to use? I personally enjoy Wii Speak a lot more. There is no delay within having fun with friends unlike the keyboard. And you don't have to put down the wii mote when you need to talk.
EDIT: Please do not vote for the blank middle. It was an accident.
Personally WiiSpeak, but just with friends I know in real. I think hearing all your voices spoils it lol (just my opinion) but in general I think WiiSpeak is better xD